The primary long-term objective of this research is to provide biomedical scientists with knowledge needed to accurately identify tick vectors of microorganisms on a worldwide basis and provide information on tick-host relationships, distributions, ecology, etc. This will be done by locating the U.S. National Tick Collection and its curators in a stable university setting surrounded by an extremely active and stimulating roup of medical entomologists organized into an Institute of Anthropodology and Parasitology. A secondary long-term goal is to create an environment conducive to training students in tick systematics. Tick-borne pathogens continue to threaten human and other animals on a global scale and incorrect identification of vectors of microorganisms can result in devastating consequences. Specific aims of this research proposal are: (1) Conduct SEM studies of the nymphal stages of the genus Ixodes in the United States and produce a monograph on them including keys. This genus includes the major vectors of the Lyme disease spirochetes; (2) an SEM study of the immature stages of Amblyomma ticks serving as vectors of heartwater disease in Africa and the Caribbean area; (3) preparation of a handbook on the Rhipicephalus species of Africa. Rhipicephalus species transmit the agents of boutonneuse fever in man and East coast fever in animals, plus other pathogens; (4) a cladistic study of the higher taxa of ticks to generate an hypothesis of phylogenetic relationships; (5) a cladistic study at the sugeneric and species level of the medically important genus Hyalomma (vectors of Crimean Congo Hemorrhagic Fever) in Pakistan. Techniques will include light and phase contrast microscopy along with scanning electron microscopy; morphometric analysis using IBM- based image analysis systems with appropriate hardware and software; and cladistic analysis using both the PAUP (Phylogenetic Analysis Using Parsimony) and Hennig 86 algorithms.